Robotic machines may be used for a number of purposes but for assistance and easy description of the invention we will consider the machine being used in association with a self mobile vacuum cleaner.
Such machines have a means to cause them to operate in various directions and have a computer system associated therewith whereby the machine can remember which parts of a room it has cleaned and also it is necessary for the machine to be able to note when it strikes an obstruction, partly to be able to move away from the obstruction at the time but also so as to avoid the obstruction in the future whilst still cleaning the remainder of the floor.
The types of obstructions can be both solid obstructions on the floor, such as pieces of furniture, walls or incursions into the room of such things as benches or the like and can also be “negative” obstructions such as a stair or step down which the machine will fall if not stopped.
As far as the positive instructions are concerned there have previously been proposed various forms of bump sensors or object detection sensors for a robotic device however these are usually of a remote sensing type, which are usually IR or RF sensors, and which tend to be associated with complicating the electronics of the device and can be quite expensive.